Police in Brazil said Sunday that two people have been arrested in connection with an alleged plot to detonate a bomb at a free Lady Gaga concert in Rio de Janeiro.

The event, on Saturday, was the biggest show of the pop star’s career that drew some 2 million fans to Copacabana Beach.

Rio de Janeiro’s state police said they had worked with the Justice Ministry to disrupt an attack allegedly planned by a group that was spreading hate speech against the LGBTQ community. Police said the group sought to radicalize and recruit teenagers to carry out attacks using Molotov cocktails and improvised explosives.

“The plan was treated as a ‘collective challenge’ with the aim of gaining notoriety on social media,” the police said.

Authorities said they arrested two people in connection with the planned attack — the alleged leader of the group on illegal weapons possession charges in the southern state of Rio Grande do Sul, and a teenager on child pornography charges in Rio.

Authorities said police raided the locations of 15 suspects across several states in Brazil and confiscated phones and other electronic devices.

A spokesperson for Lady Gaga shared in a statement with The Hollywood Reporter, “We learned about this alleged threat via media reports this morning. Prior to and during the show, there were no known safety concerns, nor any communication from the police or authorities to Lady Gaga regarding any potential risks. Her team worked closely with law enforcement throughout the planning and execution of the concert and all parties were confident in the safety measures in place.”

Concert promoters did not immediately respond to a request for comment.

The Justice Ministry said members of the group falsely presented themselves online as “Little Monsters” — Lady Gaga’s nickname for her fans — in order to reach teenagers and lure them into “networks with violent and self-destructive content.”

Police said they carried out the operation quietly on Saturday, “avoiding panic or distortion of information among the population.” The ministry said there was no impact on those attending the free concert.